Birdsong is an animal model system for exploring issues in sensorimotor integration, learning and memory, and social modulation of behavior. The proposal seeks to develop an understanding of how respiratory and syringeal motor mechanisms of sound production are changed in response to altered acoustic feedback. We have developed a technique for reducing a bird's ability to vocalize. The technique can be maintained for long periods of time and is reversible. We propose to use this technique to alter acoustic feedback, and to examine how motor mechanisms of sound production change in response to this manipulation. Three experiments are proposed. The first will compare song changes in a variety of species following the partial muting procedure. The second experiment will characterize respiratory and syringeal motor compensation following the partial muting procedure, and the last experiment will compare respiratory and syringeal motor changes after deafening and damage to the vocal motor nerve. The results will be further our understanding of how vocal plasticity is manifested in motor correlates of song.